Novel fluoroquinolone derivatives inhibit growth and biofilm formation of pathogenic bacteria in aquatic animals

Abstract:

[Objective] The antibiotic resistance poses great challenges to the prevention and treatment of bacterial infections in animals, and biofilm formation is one of the main factors inducing the resistance. We determined the effects of chloropropanoyl clinafloxacin on the growth and biofilm formation of seven strains of bacteria, with a view to finding out whether chloropropanoyl clinafloxacin has antibacterial activity.[Methods] The inhibitory activity of chloropropanoyl clinafloxacin was determined by routine drug sensitivity test. The perforation method and microbroth twofold dilution method was employed to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The biofilm-forming abilities and growth rates of the seven strains exposed to sub-inhibitory concentrations of the drug were examined by crystalline violet staining. [Results] The fluoroquinolone derivative chloropropanoyl clinafloxacin showed the MIC≤10 mg/L and MBC≤48 mg/L against four Gram-negative strains and was sensitive to three Gram-positive strains (MIC≤10 mg/L and MBC≤10 mg/L). The biofilm formation and growth of the seven strains were significantly inhibited by chloropropanoyl clinafloxacin at the sub-inhibitory concentrations, which indicated that chloropropanoyl clinafloxacin had good antibacterial activity at sub-inhibitory concentrations. [Conclusion] Chloropropanoyl clinafloxacin can be used as an antibacterial agent and provides a basis for the development of new agents or drugs targeting biofilm for the treatment of bacterial infections.